Hi guys, i would like your advice on what headers to use for my car.
I've recently completed restoration on a '67 fastback with a-code 289. I rebuild the engine with 4.020" hyper pistons, ported the heads and installed hardened valve seats, added roller tip rockers and a 204/214@.050" cam.
Performance has been very underwhelming so far. I guess this mostly has to do with the 4300 autolite carb, which is a b*tch to tune (like everybody warned me), and the stock single exhaust.
As the fastback will be a councours driven car, I'm stuck with the 4300 carb, which I might have rebuild by Pony Carbs.
I plan on replacing the exhaust with a stock style dual exhaust system, either 2"or 2.25". I'm still not sure on wether or not to use headers (which will be the only deviation from stock I'll allow myself) and what type.
I had my hart set on ceramic coated tri-y headers from thorley (www.thorleyheaders.com) as I feel I will need all the torque I can get, but they are $490.99 from Summit. I could spring for the chromed ones (329,95), but I could get ceramic coated Hedman 4 in 1's for less. What to do? What kind of difference in performance will I see between headers and the stock manifolds anyway?

TIA